The invention relates to an apparatus for damping resilient wheel suspension systems in vehicles. In a known damping system of this type (German Offenlegungsschrift 35 24 862) which is the same as U.S. Pat. No. 4,936,423, to attain a so-called semiactive suspension concept, a division into passive and active damping parts is performed. An active damping part is as it was simulated: Whenever the instantaneous progress of the suspension or damping would require a supply of energy from outside, or in other words active intervention into the suspension process, existing damping options are controlled in sign (+or -) and in an amount such that the error function becomes a minimum; in other words, whenever a standard shock absorber or shock absorber strut requires a rapid induction of active compression energy, the operative damping forces for both the tension and compression stages of the shock absorber or strut are substantially nullified, for instance by opening corresponding damping valves completely or partway, depending on the conditions desired.
A semi-active suspension concept of this kind makes use of the possible advantages of so-called passive suspension, which requires no such external energy to vary rapidly ensuing damping or suspension processes, and those of so-called active suspension, in which energy is arbitrarily supplied as it was from outside the suspension region from an independent energy source such as a hydraulic pump, and combines the advantages of both systems.